Tight throat on once fired brass, do I need to turn necks?

[Corey Harris]

Hoping one of you veteran reloaders can help me with something i've never encountered before:

New batch of Norma 7mm Rem Mag, full length sized it (cam over full size not just bump sized) loaded up and they chambered and shot excellent.

After the first firing, I again FL sized, trimmed to spec, tumbled and reloaded. Upon chambering the neck/bullet is pretty tight and i'm getting marks on the bullet, but just on one side. Am I getting uneven necks that need to be turned? (pic attached)

Didn't have this issue in this barrel with any other brass. Thanks for any help in advance!

 

[rsbhunter]

Have you measured the neck od of a fired case (other brand, batch,etc) ? What is the neck od of these cases fired? What is the diameter of these bullet/case necks (loaded rounds) What kind of seating pressure is it taking to seat these rounds ? As much info as you can provide would help....rsbhunter

 

[4xforfun]

What you are writing makes no sense. "the neck / bullet is pretty tight". Are you saying that it takes a lot of force to seat a bullet in the case? Nothing you do at the reloading bench will change the throat of the rifle, but you can definatly change "neck tension.

Your pic shows scratches on only one side of the bullet. If you rotate that same cartridge and re chamber it do the scratches spread to other parts of the bullet? If it is the chamber and you rotate your cartridge 4 times at 90 drgree's each and chamber it, you will have 4 different sides with scratches. If the problem is the loaded round it won't matter what way you put the loaded round in the chamber....the scratch will always be in the same place.

Try rotating and get back to us, because you definatly have something going on.

Good luck,
Tod

 

[Corey Harris]

Have you measured the neck of of a fired case (other brand, batch,etc) ? What is the neck od of these cases fired? What is the diameter of these bullet/case necks (loaded rounds) What kind of seating pressure is it taking to seat these rounds ? As much info as you can provide would help....rsbhunter

OD on virgin brass ran through my redding die (no bushing) is .309 on both the virgin brass and the once fired brass (both FLS)
Inside Diameter on both is .280
A loaded round is .311 (so .002 neck tension right?)
Fired rounds for this lot of Norma and a different lot of Nosler brass all measures out at .314
The bullets seat easy/normal, feels the same as it always has.
When you chamber a round it takes a little more pressure than normal on the bolt to push into the chamber, then if you were to eject the bullet it takes more pressure to pull it out (like the bullet is jammed into the lands but they are not i've seated the bullet .050 off the lands and it does the same thing with fired brass)

 

[Corey Harris]

What you are writing makes no sense. "the neck / bullet is pretty tight". Are you saying that it takes a lot of force to seat a bullet in the case? Nothing you do at the reloading bench will change the throat of the rifle, but you can definatly change "neck tension.

Your pic shows scratches on only one side of the bullet. If you rotate that same cartridge and re chamber it do the scratches spread to other parts of the bullet? If it is the chamber and you rotate your cartridge 4 times at 90 drgree's each and chamber it, you will have 4 different sides with scratches. If the problem is the loaded round it won't matter what way you put the loaded round in the chamber....the scratch will always be in the same place.

Try rotating and get back to us, because you definatly have something going on.

Good luck,
Tod

Hey Tod, the scratch does not spread to other parts of the bullet. I can put it in and chamber it a bunch of times and it stays in the same place. Maybe my seating die is messed up and i'm not concentric on the seating. I have a concentrity tool, i'll check that. I scrubbed all the copper and carbon out so the chamber is clean.

 

[philip brousseau]

does your rifle have a plunger type ejector like a 700 remington? is the bearing surface of your bullet extending below the neck shoulder juncture? look into the neck for a donut. iv'e had this problem with norma brass i recently purchased. seat a fairly light weight bullet that will not reach the neck shoulder junction and see if it chambers easily. take a fired case unsized case and slide a bullet in and see if it stops at the bottom of the neck. what make and model is your rifle? let us know what you find.

 

[Brians356]

If loaded case neck OD is .002 larger than fired neck OD (really?) you have a tight chamber neck problem, or brass with very thick neck walls. Neither seems likely. Possibly a tight chamber, if the barrel was custom chambered. The marks on the bullet (always same side) could happen even without a tight chamber neck, from a crooked loaded round.

Is this an OEM mass-produced rifle?

PS is the Redding die a standard FL, or exactly which type?
-

 

[mikecr]

His .309 was after sizing new/fired, then .311 loaded.
His fired OD is .314, or 3thou over loaded. That's a chamber neck of ~.315, so he has ~4thou of neck clearance (plenty).
Maybe his throat isn't centered, combined with high runout.

 

[Corey Harris]

His .309 was after sizing new/fired, then .311 loaded.
His fired OD is .314, or 3thou over loaded. That's a chamber neck of ~.315, so he has ~4thou of neck clearance (plenty).
Maybe his throat isn't centered, combined with high runout.

Guys I think I figured it out, let me know what you think...

I just took some of the virgin norma brass that I had previously FL sized a few weeks ago AND a once fired case and ran both of them through my redding standard FL sizing die. I seated a dummy round with a bullet and BOTH of those rounds had runout of .004-.005. Compared to the new brass I sized a few weeks ago had only .001 of runout. I think I may have damaged my sizing die somehow and it's creating an off centered loaded round.

For the record it's a Savage action (plunger/ejector) and it's a Proof Research carbon barrel i've run over 500 rounds through with no problems. Would a damaged sizing die/rod/decapper cause this isssue?

 

[4xforfun]

I didn't read all of the posts, but there are no scratches on the neck of the case....only on the bullet, so loaded diameter vs unloaded vs. ??? makes no difference..... nor does bushing size on the die.

Now, if the brass is VERY, very thick on one side and the bullet is not centered, that could make a difference, but that, too, would show up with a mic.

Something is up....

 

[rsbhunter]

I am definitely NOT an expert, but that much run out shouldn't cause mechanical problems..fl size a case with the neck expander button/decapper stem removed....measure the od of the neck, or the od of the expander button . Is the neck excessively being sized/expanded by the die? Does it help if you leave the decapping/expander button stem a little loose, so it can center it's self entering and exiting the case ? Lastly try coloring the neck with a powder or marker, and see if it is being scrapped off during loading or extraction....hope you find the problem ....rsbhunter

 

[4xforfun]

Yep...a bent or crooked die would do it!!

The hardest part of fixing most problems is knowing the cause, and this one is easy to fix!!

Tod

 

[Brians356]

His .309 was after sizing new/fired, then .311 loaded.

Duh. Too early - BC (before coffee). Thanks.
-

 

[Brians356]

OP, I ask again - which specific model of Redding die are you using?

It's virtually impossible to damage a die by sizing cases (except possibly to scratch it internally, with gritty cases.) There's no way the run-out was induced by a "bent" die, unless it was manufactured that way - highly unlikely. You said the first loads had .001 run-out after sizing, did you not?
-

 

[4xforfun]

I am definitely NOT an expert, but that much run out shouldn't cause mechanical problems..fl size a case with the neck expander button/decapper stem removed....measure the od of the neck, or the od of the expander button . Is the neck excessively being sized/expanded by the die? Does it help if you leave the decapping/expander button stem a little loose, so it can center it's self entering and exiting the case ? Lastly try coloring the neck with a powder or marker, and see if it is being scrapped off during loading or extraction....hope you find the problem ....rsbhunter

If the die is bent enough and the bullet is going in 1/2 sideways it could just be enough to scratch one side if the bullet.

 

[Corey Harris]

OP, I ask again - which specific model of Redding die are you using?

It's virtually impossible to damage a die by sizing cases (except possibly to scratch it internally, with gritty cases.) There's no way the run-out was induced by a "bent" die (my description, FWIW.)
-

https://www.midwayusa.com/product/1016308644/redding-premium-series-deluxe-3-die-set

 

[Brians356]

https://www.midwayusa.com/product/1016308644/redding-premium-series-deluxe-3-die-set

Ok, that's a conventional FL die. I'll wager the price of the die it's not "bent" in the slightest.
-

 

[rsbhunter]

Brian's356, I agree 100%'..because it worked fine with brand new cases, and cases before these, I wouldn't think the sizer die to be the culprit. Is the base of the case being sized? We're the loads hot? Is there any light scratching near the belt area of the cases? Maybe put a marker line about an inch and a half from the belt upwards and see if it's the base sizing.....by the way, and I should have asked this way back, does it do this with an empty New, once fired, sized case?...rsbhunter

 

[Willie]

Sometimes it's real simple.
(1) The scratches on the bullet and increased runout are due to a burr in the bullet chamber of the seater. I've had 2 Redding seaters returned to have that area cleaned up this year. I was getting 5-6 thou runout on seating.

(2) If the OP set up his FL sizer on the new brass and did not re-adjust the bump for fired brass to chamber, well that would explain the hard bolt closure.

(3) I'd also check for a donut forming, even though his seating is easy.

Just my thoughts.

 

[rsbhunter]

I could see that, but the op stated that rounds seated with week old brass had .001 run out....so unless something happened to the seater in the mean time....plus as to not bumping the shoulder back, that could definitely be the bolt closing problem, but it doesn't explain the hard extraction....Does the OP have a way to measure from the base to the datum line to check for shoulder bump? Might be a part of the problem....or not..he stated he has only experienced this since the new brass, so I thought he had previous reloads that had functioned without issue.......rsbhunter